noun

1. A path through two or more points (compare ‘segment’); a continuous mark, including as made by a pen; any path, curved or straight.

   “The arrow descended in a curved line.”

2. A rope, cord, string, or thread, of any thickness.

3. A hose or pipe, of any size.

   “a brake line”

Synonyms: epistle, letter, note, line of engagement, lineup, queue

verb

1. To place (objects) into a line (usually used with "up"); to form into a line; to align.

   “to line troops”

2. To place persons or things along the side of for security or defense; to strengthen by adding; to fortify.

   “to line works with soldiers”

3. To form a line along.